The invention pertains to methods of forming conductive interconnects.
Conductive interconnects are frequently used for connecting portions of integrated circuitry. Conductive interconnects can extend either vertically or horizontally, depending on their particular application. For instance, vertically extending conductive interconnects (conductive plugs) can be utilized for connecting circuitry at one elevational level with an electrical node at a different elevational level. An exemplary prior art conductive plug is described with reference to a semiconductive wafer fragment 10 in FIG. 1.
Wafer fragment 10 comprises a substrate 12, and an insulative material 14 overlying substrate 12. Substrate 12 can comprise, for example, monocrystalline silicon lightly doped with a p-type conductivity-enhancing dopant. To aid in interpretation of the claims that follow, the term xe2x80x9csemiconductive substratexe2x80x9d is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term xe2x80x9csubstratexe2x80x9d refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. Insulative material 14 can comprise, for example, borophosphosilicate glass (BPSG).
An electrical node 16 is supported by substrate 12, with node 16 being at an electrical node location of substrate 12. In the shown structure, electrical node 16 comprises a diffusion region formed within substrate 12. Such diffusion region can be formed by implanting a conductivity-enhancing dopant within substrate 12 to a concentration which creates the electrically conductive region 16.
An opening 20 extends through insulative layer 14 and to electrical node 16. A silicide layer 22 is provided at a bottom of opening 20 and over electrical node 16, a titanium nitride barrier layer 21 is formed over silicide layer 22, and a conductive plug 24 is provided over silicide material 22. Conductive plug 24 comprises a metal, such as, for example, tungsten, and can be formed by, for example, sputter deposition.
Silicide material 22 can be formed by depositing a silicide, such as, for example, titanium silicide, over electrical node 16.
A conductive material 33 is provided over insulative material 14 and in contact with plug 24. Plug 24 thus functions as a conductive interconnect between the elevationally upper circuitry of material 33 and the elevationally lower circuitry of node 16. In the shown construction, plug 24 and insulative layer 14 comprise a common and planarized upper surface 30. Such planarized upper surface can be formed by, for example, chemical-mechanical polishing.
As conductive interconnects are utilized in numerous circuitry constructions, it would be desirable to develop alternative methods of forming conductive interconnects.
In one aspect, the invention includes a method of forming a conductive interconnect. An electrical node location is defined to be supported by a silicon-containing substrate. A silicide is formed in contact with the electrical node location. The silicide is formed by exposing the substrate to hydrogen, TiCl4 and plasma conditions to cause Ti from the TiCl4 to combine with silicon of the substrate to form TiSix. Conductively doped silicon material is formed over the silicide. The conductively doped silicon material is exposed to one or more temperatures of at least about 800xc2x0 C. The silicide is also exposed to the temperatures of at least about 800xc2x0 C.
In another aspect, the invention includes another method of forming a conductive interconnect. A silicon-comprising electrical node is supported by a substrate. An insulative material is formed over the substrate. The insulative material has an opening therein which extends to the electrical node. A silicide is formed within the opening and over the electrical node. The silicide is formed by exposing the electrical node to hydrogen, TiCl4 and plasma conditions to cause Ti from the TiCl4 to combine with silicon of the node to form TiSix. A conductive barrier layer is formed over the silicide within the opening. A conductively doped silicon material is formed over the barrier layer within the opening. The barrier layer protects against migration of dopant from the conductively doped silicon material to the silicide.